I live in Indonesia and here there are some fuel companies like Shell and AVR but a majority uses Pertamina. My car uses 95 octane Pertamax that costs about Rp 9850,- per litre (1 gallon = 3.785 litre and US $1 = Rp 14000,-) or about $ 2.66 per gallon. I'll make a list of how much it costs here:
Premium 88 - Rp 7000,- per litre or $ 1.89 per gallon
Pertalite 90 - Rp 7650,- per litre or $ 2.06 per gallon
Pertamax 92 - Rp 9850,- per litre or $ 2.66 per gallon
Pertamax Turbo 98 - Rp 11200,- per litre or $ 3.02 per gallon
Those are the petrol ones, here's the diesel ones:
Bio Solar - Rp 9800,- per litre or $ 2.65 per gallon
Dexlite - Rp 10200,- per litre or $ 2.75 per gallon
Pertamina Dex - Rp 11700,- per litre or $ 3.16 per gallon
There is one more petrol fuel sold in a few places, it's called Pertamax Racing with 100 octane that costs about Rp 42000,- to Rp 44500,- per litre or about $ 11.35 to $ 12.03 per gallon. It's probably only sold in Jakarta (where actual luxury and sports cars are).